Serious question: How many pills does it take? Or do you take one every time you have sex? Like the condoms the guy isn’t using?
They only work for 48 hours. They suppress ovulation and also prevent implantmentation for than time window. You have to take one side following each suspected event. The most common being if a condom breaks or falls off. In theory if a woman knew here cycle well enough and was confident in it then you would only need two dose use them right after the ovulation event and the body will pass the egg in that 72 hour window then pregnancy is not possible till the following cycle. Problem is some women double ovulate and its nearly impossible to know the exact ovulation event even with hormonal urine monitoring at the lab grade level. So back to the original on label use after every suspected event.
I have know at least a dozen young women not tolerant of hormonal contraceptives and at least that many with latex allergies. For the latex there are synthetic rubbers that are in the same 90% effective window.
Note to women queuing for the morning after pill: It won’t cure STDs, ladies.